Constants

START_STICKY

Constant to return from onStartCommand(Intent, int, int): if this
service's process is killed while it is started (after returning from
onStartCommand(Intent, int, int)), then leave it in the started
state but don't retain this delivered intent. Later the system will try to
re-create the service. Because it is in the started state, it will
guarantee to call onStartCommand(Intent, int, int) after creating
the new service instance; if there are not any pending start commands to be
delivered to the service, it will be called with a null intent
object, so you must take care to check for this.

This mode makes sense for things that will be explicitly started
and stopped to run for arbitrary periods of time, such as a service
performing background music playback.